MOOGP-I Servoamplifier G122-829A001

Application Notes

1 Scope

These Application Notes are a guide to applying the 

G122-829A001 P-I Servoamplifier. These Application Notes 

can be used to:

 Determine the closed loop structure for your application.

 Select the G122-829A001 for your application. Refer also 

to data sheet G122-829.

 Use these Application Notes to determine your system 

configuration.

 Draw your wiring diagram.

 Install and commission your system.

Aspects, such as hydraulic design, actuator selection, feedback 

transducer selection, performance estimation, etc. are not 

covered by these Application Notes. The G122-202 Application 

Notes (part no C31015) cover some of these aspects. Moog 

Application Engineers can provide more detailed assistance, 

if required.

2 Description

The G122-829A001 is a general purpose, user configurable,

P-I servoamplifier. Selector switches inside the amplifier enable 

either proportional control, integral control, or both to be 

selected. Many aspects of the amplifier’s characteristics can 

be adjusted with front panel pots or selected with internal 

switches. This enables one amplifier to be used in many 

different applications. Refer also to data sheet G122-829.

3 Installation

3.1 Placement

A horizontal DIN rail, mounted on the vertical rear surface 

of an industrial steel enclosure, is the intended method of 

mounting. The rail release clip of the G122-829A001 should 

face down, so the front panel and terminal identifications 

are readable and so the internal electronics receive a cooling 

airflow.

An important consideration for the placement of the module 

is electro magnetic interference (EMI) from other equipment 

in the enclosure. For instance, VF and AC servo drives 

can produce high levels of EMI. Always check the 

EMC compliance of other equipment before placing 

the G122-829A001 close by.

3.2 Cooling

Vents in the top and bottom sides of the G122-829A001 case 

provide cooling for the electronics inside. These vents should 

be left clear. It is important to ensure that equipment below 

does not produce hot exhaust air that heats up the G122-829

3.3 Wiring

The use of crimp “boot lace ferrules” is recommended for the 

screw terminals. Allow sufficient cable length so the circuit 

card can be withdrawn from its case with the wires still 

connected. This enables switch changes on the circuit card 

to be made while the card is still connected and operating. 

An extra 100mm, for cables going outside the enclosure, 

as well as wires connecting to adjacent DIN rail units, 

is adequate.

The screw terminals will accommodate wire sizes from 

0.2mm2 to 2.5mm2 (24AWG to 12AWG). One Amp rated, 

0.2mm2 should be adequate for all applications.

3.4 EMC

The G122-829A001 emits radiation well below the level called 

for in its CE mark test. Therefore, no special precautions are 

required for suppression of emissions. However, immunity from 

external interfering radiation is dependent on careful wiring 

techniques. The accepted method is to use screened cables for 

all connections and to radially terminate the cable screens, in 

an appropriate grounded cable gland, at the point of entry into 

the industrial steel enclosure. If this is not possible, chassis 

ground screw terminals are provided on the G122-829A001. 

Exposed wires should be kept to a minimum length. Connect 

the screens at both ends of the cable to chassis ground.

4 Power supply

24V DC nominal, 22 to 28V

75mA @ 24V without a load, 200mA @ 100mA load.

If an unregulated supply is used the bottom of the ripple 

waveform is not to fall below 22V.

It is recommended that an M205, 250mA T (slow blow) fuse, 

compliant with IEC127-2 sheet 3, be placed in series with the 

+24V input to protect the electronic circuit. If terminal 23 is 

used to power a proportional valve, the fuse should be 

increased to cater for the extra current

Caution

If you intend to use the feedback amplifier adjusted for 

4-20mA, don’t change the feedback gain or zero.

 They are already adjusted for 4-20mA

 To re-adjust for 4-20mA takes a little time, needs test 

equipment and is tedious to do in the field.

6 Input configuration

Inputs 1, 2 and feedback go to the error amplifier and can be 

used for feedback or command. Care needs to be taken in 

selecting signal polarity to achieve negative feedback for 

the overall closed loop. Since the input error amplifier sums 

the signals, the transducer feedback signal needs to be the 

opposite polarity of the command. This can be achieved in 

two ways:

 Arrange for an opposite polarity feedback transducer signal 

and connect it to input 1, input 2 or the positive feedback 

amplifier input.

 If the feedback transducer signal is the same polarity as the 

command, you only have one option: Connect it to the 

negative input of the feedback amplifier.

6.1 Feedback input

An input to the error amplifier: The feedback amplifier is the 

best choice for the feedback signal, for six reasons: