Macro 12 (p0015 = 12) uses DI0 for ON/OFF1, DI1 for reverse, DI2 for acknowledge and AI0 for the speed reference. Choosing the macro does not calibrate the signal: the DIP switch, p0756 and the endpoints p0757–p0760 must all agree. Check it with r0752 (raw) and r0755 (%).
- A changing AI is never a start command.
- Set p0756 first, because changing it can reset the endpoints.
- 4–20 mA: subtract 4, divide by 16.
- A zero reference is not a safety stop.
Separate the Run Command from the Speed Reference
The command path (DI0) and the reference path (AI0) are independent. Write a signal list first: controller output range, drive input channel, engineering range, broken-signal response, CU order number and firmware.
Match the Electrical Input and Parameter Type
Set the AI0 DIP switch with power isolated, then set p0756, and only then the endpoints. Use the parameter index for the input you actually wired (index 0 = AI0).
| Parameter | Meaning | Check |
|---|---|---|
| p0756 | Input type (0 = 0–10 V, 3 = 4–20 mA monitored) | Matches the DIP switch and the source |
| p0757 / p0758 | Point 1: input value / % | Low endpoint |
| p0759 / p0760 | Point 2: input value / % | High endpoint |
| r0752 / r0755 | Measured input / scaled % | Compare electrical and scaled values |
| p2000 | Reference speed (= 100 %) | What 100 % means in the project |
Calibrate a real analogue loop
Hands-on G120 training with calibrators, PLC analogue outputs and live drives — Pune or online.
Worked 0–10 V and 4–20 mA Scaling (Live Calculator)
% = Y1 + (Input − X1) × (Y2 − Y1) / (X2 − X1), then Hz = % / 100 × 50. The red dashed line shows the classic mistake of dividing 12 mA by 20.
Assumes 100 % = 50 Hz (p2000), no extra setpoint or limits. Drag the slider, or let it sweep. At 0 the 4–20 mA mode shows the wire-break case.
| Input range | Low | Mid | High |
|---|---|---|---|
| 0–10 V | 0 V → 0 % → 0 Hz | 5 V → 50 % → 25 Hz | 10 V → 100 % → 50 Hz |
| 4–20 mA | 4 mA → 0 % → 0 Hz | 12 mA → 50 % → 25 Hz | 20 mA → 100 % → 50 Hz |
If the process needs a minimum speed, create it in one place only (the characteristic, a drive limit or the PLC) and write down which.
EPLAN Terminal Wiring: Local Pot and PLC 4–20 mA
Two typical macro 12 installations: a local 10 kΩ potentiometer (0–10 V), and a PLC giving commands plus a 4–20 mA reference with feedback. Step through each circuit.
- Supply and commonsFused PELV L+ feeds CU terminal 31, with 32 to M. DI COM1 (69) and GND (28) go to M for source (PNP) inputs, so the drive and field devices share one reference.
- Run command ≠ speedMacro 12 puts ON/OFF1 on DI0 (-S1), reverse on DI1 (-S2) and acknowledge on DI2 (-S3). A changing analogue signal never starts the drive, and a zero reference is not a safety stop.
- Local speed pot 0–10 V-R2 sits across +10 V (1) and GND (2), with the wiper on AI0+ (3) and AI0− (4) linked to GND. It runs on screened cable with the shield on the CU plate. Set the DIP to U, p0756 = 0 and endpoints 0 V/0 % … 10 V/100 %.
- IndicationRelay DO0 (20 → 19) lights the fault lamp -H1, and AO0 (12/13) drives actual-speed meter -P1. Macro 12 sets these by default; check p0730 and p0771.
- PLC commandsPLC outputs DQ0–DQ2 drive DI0–DI2 through -X1 terminals. The PLC M and the drive M are the same 0 V, otherwise the inputs do not see a valid 24 V.
- 4–20 mA reference from the PLCPLC AQ0 (current) feeds AI0+ (3) / AI0− (4) on a screened pair, with the shield on the CU plate. Set the DIP to I, p0756 = 3 (monitored) and endpoints 4 mA/0 % … 20 mA/100 %. A broken loop is then detected instead of reading as a valid zero.
- Feedback to the PLCAO0 (12/13) returns actual speed to a PLC AI on screened -W4, with the type matched in p0776. The DO0 relay reports a drive fault to a PLC DI. The HMI value is then measured, not assumed.
| From | To CU240E-2 | Signal | Setting / check |
|---|---|---|---|
| L+ / M | 31 / 32 | CU 24 V supply | CU powers up |
| M | 69, 28 | DI COM1, GND | source wiring |
| -S1 or PLC DQ0 | 5 (DI0) | ON/OFF1 | r0722.0 |
| -S2 or PLC DQ1 | 6 (DI1) | Reverse | r0722.1 |
| -S3 or PLC DQ2 | 7 (DI2) | Acknowledge | r0722.2 |
| -R2 pot | 1 / 3 / 2, link 4–2 | 0–10 V reference | DIP U, p0756 = 0, r0755 |
| PLC AQ0 I / M | 3 / 4 | 4–20 mA reference | DIP I, p0756 = 3, r0752 in mA |
| 12 / 13 | -P1 or PLC AI | Actual speed (AO0) | p0771, p0776 |
| 20 → 19 | -H1 or PLC DI | Fault relay | p0730 = r0052.3 |
Training drawing for a CU240E-2 (macro 12). Check terminals against the manual for your CU and firmware. The full panel, including power and STO, is in G120 wiring and terminal parameters.
Find Scaling and Signal-Loss Faults
Keep run permission and signal quality as separate checks. A plausible number on an HMI does not prove the drive is getting a healthy reference.
Practical Lab: Verify the Whole Signal Chain
Hands-on- A G120 with CU240E-2 on a training rig, macro 12 applied, motor uncoupled or on a light load.
- A 10 kΩ potentiometer or a mA/V calibrator, and a multimeter. Estimated time: 45 minutes.
Back up and record
Upload the project, note the command source, and confirm macro 12 exists for your CU and firmware.
Confirm the electrical value
With motion inhibited, measure the real voltage or current at AI0 (terminals 3/4).
Three-point test, rising and falling
Apply low, mid and high (0/5/10 V or 4/12/20 mA) going up, then down. Record r0752, r0755 and the expected Hz.
Locate any error
Raw OK but % wrong: check p0756, the index and p0757–p0760. % OK but Hz wrong: check p2000 and the setpoint path.
Controlled motion test
Only after the static checks pass, run DI0 and compare actual speed once the ramp has settled.
Signal-loss test
With an approved procedure, open the 4–20 mA loop. Record the fault and the drive response, then reset.
Save and document
Set p0971 = 1, upload, and record the calibrator used.
Raw, scaled and requested values agree at every test point in both directions, motion follows the request, and a broken loop produces a documented fault.
Frequently asked questions
Does macro 12 automatically configure 4–20 mA?
No. Macro 12 only connects DI0/DI1/DI2 and AI0. You still set the DIP switch to I, p0756 = 3 for monitored 4–20 mA, and the endpoints p0757–p0760, then verify the low, middle and high points.
Which parameters scale the G120 analogue input?
p0756 sets the signal type, p0757/p0758 set the first point (input, %), and p0759/p0760 set the second point. r0752 shows the measured input and r0755 the scaled percentage. p2000 defines what 100 % means.
Why does 12 mA give 60 % instead of 50 %?
Because 12 was divided by 20. For 4–20 mA, subtract the 4 mA live zero and divide by the 16 mA span: (12 − 4) / 16 = 50 %.
Why does 5 V not give 25 Hz?
That only holds if 0–10 V maps to 0–100 % and 100 % is 50 Hz, with no other setpoint or limit in the way. Check r0752, then r0755, then the request, in that order.
How do I wire a PLC 4–20 mA output to G120 AI0?
Connect the PLC current output to AI0+ (terminal 3) and its reference to AI0− (4) with a screened pair, shield clamped on the CU shield plate. Set the DIP switch to I and p0756 = 3, and share the 0 V between PLC and drive.
Is removing the analogue reference an emergency stop?
No. Use the machine’s designed and validated safety function, such as STO. Loss of the reference also needs its own documented response.
Technical references
Use the edition that matches your hardware and firmware. The manuals establish the device facts; the worked values, calculator and drawings are training examples.