13.2
Setting of the internal half-bridge converter for SE Ex sensors
The half-bridge converter must be in a Dräger REGARD 2400 and be supplied with power for
comparison. A Polytron SE Ex sensing head must be connected.
Compare power supply of the half-bridge
1. The power supply of the half-bridge is measured at the 2 'half-bridge power' measuring
points using a voltmeter.
2. At the Polytron SE Ex PR M sensing head for example, this power is 270 mA and
is preset. All other pellistor sensing heads must be set in accordance with their specification.
3. The power can be altered using the potentiometer 'Comparison of the power supply of
the sensor'. The power-measurement voltage ratio is described in the following table.
Power supply of the
half-bridge in mA
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
Dräger REGARD 2400/2410
Voltage measuring
point half-bridges
power in V
1.248
1.253
1.258
1.263
1.268
1.273
1.278
1.283
1.288
1.293
1.298
1.303
1.308
1.313
1.318
1.323
1.328
1.333
1.338
1.343
1.348
1.353
1.358
1.363
1.368
1.373
Power supply of the
half-bridge in mA
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
Maintenance
Voltage measuring
point half-bridges
power in V
1.373
1.378
1.383
1.388
1.393
1.398
1.403
1.408
1.413
1.418
1.423
1.428
1.433
1.438
1.443
1.448
1.453
1.458
1.463
1.468
1.473
1.478
1.483
1.488
1.493
1.498
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