Toshiba TIC-LF494B manual Wiring Precautions Profibus, Meter Size, To select the meter size

TIC-LF494B

Wiring Precautions

(1)Explosion proof type flowmeters are not provided cable glands.

Refer to the part Cable connection port at detector and converter.

(2)Connect the grounding wire (IV wire 5.5mm² or more) to a good earth ground (100Ω or less ground resistance). Make the wire as short as possible. Do not use a common ground shared with other equipment where earth current may flow. An independent earth ground is recommended.

(3)The allowable cable lengths between the detector and converter for the separate type flowmeter depend on the electrical conductivity of the object fluid. See Figure 11.

(4)DO1, DO2 (opt.), and DI (opt.) use the same common terminal (COM). This COM can not connect to other equipments which have their own ground terminal. (Power supply for connecting to DI or DO, etc…) Need to wire separately.

Wiring Precautions (PROFIBUS)

(1)For wiring path, avoid places near electrical equipment that may cause electromagnetic induction or electrostatic induction interference (such as a motor, transformer and wireless transmitter).

(2)Use a PROFIBUS-PA cable for signal cable. In addition, make sure to use a shielded cable to improve noise resistance. Furthermore, installation of signal cable in metal conduit is recommended.

(3)General PROFIBUS-PA cables are designed for indoor use where cables are not exposed to humidity, rain, etc. When you install cables, make sure to check the operating conditions such as the operating temperature range of the cable by contacting its manufacturer.

(4)When you carry out cable end treatment of PROFIBUS-PA cable, use a dedicated cable stripper etc. so that the core wire of the cable will not be nicked or damaged. In addition, for cables, be careful of allowable maximum bend diameter etc. (Basically, do not install cables in a way cables are twisted or bent.).

(5)Consider installing a PROFIBUS-PA arrester in the communication path of PROFBUS-PA so that the electromagnetic flowmeter will not be affected by lightning etc.

(6)The electromagnetic flowmeter is not equipped with terminating resistors.Use the terminating resistor unit for PROFIBUS-PA or junction box, if necessary.

(7)Only one PROFIBUS-PA cable goes through a cable gland of the Electromagnetic Flowmeter. Please use the junction box at system configuration.

	300
(m)	200
	100
	50
cable length
	30
	10
Allowable	5
	3
	3	5	10 20 30	50 100 200
		Conductivity (∝S/cm)

Figure 11. Electrical Conductivity and

Cable Length

Meter Size

To select the meter size:

See Table 2 to 3 and find meter sizes within the velocity of 0.3 to 32.8 ft/s (0.1 to 10m/s ) for a specified full-scale (measuring range high limit) flow. Select one that has its full-scale velocity between 3.0 and 10 ft/s (1 and 3m/s).

Note: Make sure the full-scale flow rate used for the final planning stage stays within 32.8 ft/s (10m/s) in terms of flow velocity.

Table 2. Flow Rate and Flow Velocity (English unit)

Unit: gal/min

Size			Flow rate
(inch)	0.3ft/s	0.98ft/s	3ft/s	10ft/s	32.8ft/s
1	0.7781	2.334	7.115	23.72	77.81
1 ½	1.992	5.975	18.21	60.71	199.2
2	3.112	9.337	28.46	94.86	311.2
3	7.967	23.90	72.85	242.8	796.7
4	12.45	37.35	113.8	379.4	1,245

Table 3. Flow Rate and Flow Velocity (SI unit)

Unit: m3/h

Size			Flow rate
(mm)	0.１ m/s	0.3 m/s		1.0 m/s	3 m/s	10 m/s
25	0.1767	0.5301		1.767	5.301	17.67
40	0.4523	1.357		4.523	13.57	45.23
50	0.7067	2.120		7.067	21.20	70.67
80	1.809	5.428		18.09	54.28	180.9
100	2.827	8.482		28.27	84.82	282.7

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