The indicating transmitter DTR is only compatible with the PR-21-S refractometers and the PR-23 range. Any one or two PR-21-S refractometer sensors can be connected to the DTR. PR-01 and PR-03 refractometer sensors are not compatible with an indicating transmitter DTR.
For intrinsically safe installations (see Section 10.4) there is a single-sensor version of the transmitter (STR). The information given in this chapter applies to STR as well, unless otherwise indicated.