Datasheet

Ip251_02b_oi_e.doc / Dez-15 Page 6 / 28
2. Introduction
IP251 represents a small and low-cost, but highly performing converter for industrial
applications, where the information of a sensor or encoder with SSI interface needs to be
converted to a parallel signal or a serial RS232 data format. Also it is possible to convert serial
RS232 data to a parallel format.
The unit has been designed as a compact module with 12 screw terminals, a 9-position and a
25-position SUB-D connector (female). The housing is suitable for simple and quick snap-on
mounting on a top hat rail (according to the EN 60715 standard).
2.1. Applicable encoders and sensors:
Single-turn or multi-turn absolute encoders and all similar sensors using a standard SSI
interface (6 to 25 bits of resolution with binary or Gray code). The unit can operate in either
 Master mode (clock signal generated by the IP251 unit), or in
 Slave mode (clock signal generated by a remote device)
2.2. Remark about the encoder resolution:
The unit provides settings for the standard resolutions of 13 bits, 21 bits and 25 bits. In general,
for sensors with other resolutions you can use the next higher setting (i.e. set the unit to 21 bits
with a sensor of 16 bits).
Depending on brand and specification of the encoder, in some cases it may be necessary to
blank out the surplus bits by using the bit blanking function described later. In general however,
the unit should work perfectly also without special bit blanking.
3. Terminal Assignment
The subsequent diagram shows the assignment of the screw terminals. GND terminals 4 and 6
are connected internally. Depending on input voltage and load of the auxiliary voltage output,
the total power consumption of the unit is about 200 mA.
1
2
3
4
5
6
7
8
9
1
0
1
1
1
2
COM + (+5....+27V max)
SSI- Clock (-)
SSI- Clock (+)
GND ( - )
+18...30 VDC (typ. 200 mA)
NC
SSI Data (-)
SSI Data (+)
Hold
GND ( - )
P
O
W
E
R
NC
NC
We recommend to connect the Minus wire of the power supply to earth potential.