ES-7656 Rev.10

27U

Head-mounted Two-wire Signal Conditioners
27-UNIT

2-WIRE UNIVERSAL TEMPERATURE TRANSMITTER

(PC programmable)
Functions & Features
• Universal input: mV, T/C, RTD and resistance
• Suitable for Functional Safety applications up
to SIL2
• Programming via PC Configurator
• A wide variety of T/C and RTD types
• User’s temperature table can be used
• Self diagnostics
• Low temperature drift
• CE marking (conforms to ATEX and EMC)

MODEL: 27U–[1]

ORDERING INFORMATION

• Code number: 27U-[1]
Specify a code from below for [1].
  (e.g. 27U-0)
Use Ordering Information Sheet (No. ESU-7656). Factory standard setting will be used if not otherwise specified.
Specify the country in which the product is to be used with the Safety Approval code 2.

[1] SAFETY APPROVAL

0: None
1: FM intrinsically safe
2: ATEX intrinsic safety

RELATED PRODUCTS

• USB interface Bell202 modem (model: COP-HU)
Usable in ‘non-hazardous’ area only.
• PC configurator software (model: 27MCFG)
Downloadable at our web site.

GENERAL SPECIFICATIONS

Construction: Sensor head-mounting
Connection: M3 screw terminals (torque 0.5 N·m)
Screw terminal: Nickel-plated brass
Housing material: Flame-resistant resin (black)
Isolation: Input to output
Cold Junction Compensation: CJC sensor incorporated
Self diagnostics: Detects internal error, burnout
User-configurable items: PC and the transmitter are connected with the COP-HU.
• Input sensor type
• Input range
• Burnout
• Output limits (Upper / Lower)
• Damping time (factory set to 0)
• Linearization
• Output calibration
• Loop test output

INPUT SPECIFICATIONS

The input is factory set for use with K thermocouple, single input, 0 to 100°C.
See Table 1 for the available input type, the minimum span and the maximum range.
DC mV
Input resistance: ≥ 1 MΩ
Thermocouple (dual input available)
Input resistance:
≥ 1 MΩ
RTD (2-wire, 3-wire or 4-wire)
Input resistance:
≥ 1 MΩ
Excitation: ≤ 0.25 mA
Allowable leadwire resistance: Max. 10 Ω per wire
Resistance (2-wire, 3-wire or 4-wire)
Input resistance:
≥ 1 MΩ
Excitation: 0.25 mA
Allowable leadwire resistance: Max. 10 Ω per wire

OUTPUT SPECIFICATIONS

Output range: 4 – 20 mA DC
Operational range: 3.75 – 23 mA
Load resistance vs. supply voltage:
Load Resistance (Ω) = (Supply Voltage (V) – 9 (V)) ÷ 0.023 (A)   (including leadwire resistance)
Burnout: 3.75 – 3.8 mA or 21.5 – 23 mA
(factory set to 23 mA)
Upper output limit proportional to the input:
20 – 21.5 mA (factory set to 21.5 mA)
Lower output limit proportional to the input:
3.8 – 4 mA (factory set to 3.8 mA)
Update time: 440 msec. (660 msec. with dual input)
Output characteristics for dual input:
Average or Differential selectable

INSTALLATION

Supply voltage
 • 9 – 35 V DC (non-approved)
 • 9 – 28 V DC (approved)
Operating temperature: -40 to +85°C (-40 to +185°F)
(See Safety Parameters for use in a hazardous location.)

Operating humidity: 0 to 95 %RH (non-condensing)
Mounting: Head-mounting (DIN type B head)
Weight: 50 g (1.76 oz)

PERFORMANCE

Accuracy: As indicated in Table 1, ±0.075 % of span
or ±0.075 % of max. range, whichever is the greatest.
Add the CJC error for T/C input.
(max. range = 0 % or 100 % value, absolute value of
whichever is greater.)
Cold junction compensation error: ±0.5°C (±0.9°F)
Temp. coefficient: 0.0075 %/°C (0.004 %/°F) of max. range
(max. range = 0 % or 100 % value, absolute value of
whichever is greater.)
Response time: ≤ 1 sec. (0 – 90 %) or ≤ 2 sec. (4-wire RTD,
4-wire resistance or dual input T/C; 0 – 90 %) with damping time set to 0
Supply voltage effect: ±0.01 % of span/V
Insulation resistance: ≥ 100 MΩ with 500 V DC
Dielectric strength: 1500 V AC @1 minute (input to output)
Safety integrity level according to IEC 61508: Suitable for use in a safety instrumented system up to SIL2 (together with sensor) if appropriate safety instructions are observed. Consult us.

STANDARDS & APPROVALS

EU conformity:
ATEX Directive 
  Ex ia EN 60079-11
EMC Directive 
  EMI EN 61000-6-4
  EMS EN 61000-6-2
RoHS Directive
Safety approval:
FM: Intrinsically safe
  Class I, Division 1, Groups A, B, C and D
  Class I, Zone 0, AEx ia IIC (US)
  Class I, Zone 0, Ex ia IIC (Canada)
  T4, T5 and T6
  (Class 3610, ANSI/ISA 60079-11,
  CAN/CSA-C22.2 No. 157,
  CAN/CSA-C22.2 No. 60079-11)

SAFETY PARAMETERS

Operating temperature
For ATEX / FM:
  T4: -40 to +80°C
  T5: -40 to +60°C
  T6: -40 to +45°C
Ex-data:
• Output circuit
  Ui (Vmax): 30 V DC
  Ii (Imax): 96 mA DC
  Pi (Pmax): 720 mW
  Ci: 1 nF
  Li: 0 mH
• Sensor circuit
  Uo (Voc): 30 V DC
  Io (Isc): 24 mA DC
  Po: 180 mW
  Co (Ca): 50 nF
  Lo (La): 40 mH

INPUT TYPE, RANGE & ACCURACY

EXTERNAL DIMENSIONS & TERMINAL ASSIGNMENTS unit: mm [inch]

MOUNTING REQUIREMENTS unit: mm [inch]

SCHEMATIC CIRCUITRY & CONNECTION DIAGRAM