A-B 1746-QV Setting Up the Hardware Synchronized Axes Control Module

Connect the LDT to

Module Inputs

We assume that you will use one of the following types of LDT:

• Temposonics II: RPM TTSRxxxxxxR, or

DPM TTSRxxxxxxDExxx

• Balluff: BTL-2-L2, or BTL-2-M2

• Santest: GYRP, or GYRG

• Gemco Quick-Stick II: 951VP, or 951 RS

We illustrate typical connections between the 1746-QV module and

these types of LDTs. (There are other suppliers with compatible LDTs.)

Connect each 1746-QV input pin # to the corresponding LDT pin #.

Connect Module Outputs

to Output Devices

Module outputs connect to a separate 2-conductor output terminal

block located beneath the input terminal block.

Note: Follow manufacturer recommendations for shielding the output

cables of the proportional amplifier. Typically, pulse-width modulated

outputs radiate electrical noise originating from the +24V dc power

supply, so isolate the shields of the amplifier output cable to a 0V dc

connection inside the proportional amplifier.

You have a choice of three configurations to match your hydraulics:

• proportional amplifier with ramp and proportional valve

• servo amplifier with ramp and variable-volume pump

• Allen-Bradley 1305 Drive and hydraulic pump

You may use either of the following output voltage ranges:

• 0-10V dc for the Allen-Bradley 1305 Drive or variable-volume pump

• –10 to +10V dc for the proportional amplifier and proportional valve

Minimizing Interference

from Radiated Electrical

Noise

Important: Signals in this type of control system are very susceptible

to radiated electrical noise. The module is designed to set the loss-ofsensor

bit I:e.0/8 and the LDT-error bit I:e.0/0 when it detects position

values that are lost or corrupted by electrical noise.

Connect module output terminals to output devices with correct bonding:

• connect power supply output commons together

• electrically isolate power supply output commons from earth ground

• use bond wires that are equal in size to signal wires

Minimize interference from radiated electrical noise with correct

shielding and grounding:

• connect all of the following to earth ground:

– LDT flange, frame, and machine

– I/O chassis

– protective ground

– AC ground

– cable shields at one end only, preferably with 3/8” braid wire

(for analog output, ±15V dc PS, 24V dc PS, and LDT)

– terminal 4 of the input terminal block

• run shielded cables only in low-voltage conduit

• place the SLC-500 processor, power supply, and I/O chassis

assembly in a suitable enclosure

Typical grounding and shielding for this type of control system:

Considerations for the

±15V dc Supply

Selection of the ±15V Power Supply

The positive and negative supply of some ±15V dc power supplies

decay at different rates when ac power is removed. The module’s

output will be biased, based upon the difference in voltage level

between the positive and negative supply. The duration is dependent

upon the magnitude of the difference and the decay rate. For these

reasons, the ±15V dc power supply should have or be equipped with:

• proper interlocks with machine operation and e-stop circuits

• an internal voltage-sense relay that drops the ±15V (without

variation in decay rates) upon loss of ac power

• auxiliary relay to indicate proper operation and voltage

(such as loss of +15V but not –15 V dc)

Application of the ±15V Power Supply

The module uses the ±15V dc power supply to drive the ±10V dc

valve output and to power the LDT. The module detects loss of

±15V dc with its internal LDT diagnostic. The diagnostic

concludes loss of ±15V when it detects loss of LDT magnet.

Partial failure of the ±15V dc power supply may cause limited

machine operation when the LDT continues to operate properly. Some

LDTs will operate with its supply voltage down to 12V. If you monitor

the ±15V dc with SLC diagnostics, you can enable a blocking valve

to lock the actuator in its last position upon detection of:

• e-stop

• power loss

• low voltage condition of the ±15V dc supply

ATTENTION: If you provide a system e-stop circuit and design the

system to manage power to the SLC chassis and ±15V dc supply, in

all cases DO NOT connect the e-stop to ac power for power supplies.